Vang Vieng - trawling for mud?

These guys were digging up mud from the river bed, for what we think must have been construction around the town. Vang Vieng was apparently once a sleepy, riverside town which is fast becoming a top tourist destination. It has a huge backpacker scene and, looking at the hotels which are being built, may now wish to begin catering more for the Luang Prabang oldsters...perhaps to drive the young drunken backpackers out...not sure. There's an island where the young ones seem to congregate so perhaps they'll try to keep the town now for the more distinguished tourists. Speculation...